This invention relates to a video camera, an image input device for inputting image data generated from the video camera, and an image input system using them. More particularly, the invention relates to a video camera, an image input device and an image input system suitable for connection with a television conference apparatus or a computer apparatus equipped with image processing functions.
A system which inputs images obtained by a video camera to a television conference apparatus or a computer having image processing functions has been employed in recent years. Generally, such a system is divided into a video camera portion for imaging images and converting them to electric signals and an image input device portion for converting the image signals taken by the video camera to a data format inside the television conference apparatus or the computer. The camera portion is accommodated in most cases in a casing separate from the main body of the television conference apparatus or the computer main body, and is connected to the image input devices accommodated in the main body through cables, etc. The image data is handled as digital data inside the television conference apparatus or the computer. Image signal processing inside the camera, too, is digitized. In such an apparatus, therefore, the signal transfer by a digital system is more advantageous than an analog system because an analog-to-digital conversion process can be eliminated, a circuit scale can be reduced and image quality can be improved. In recent video camera and image inputting device of this kind, the video camera main body portion and the image input device portion are connected with each other by cables for the digital signals as described, for example, in JP-A-6-276547 and IEEE Transactions on Consumer Electronics, Vol. 39, NO. 3 pp. 467 to 473 August 1993.
In the apparatus or system described above according to the prior art, transfer of the image data between the video camera and the image input device is made by digital signals including a luminance signal and a color difference signal. For this reason, a signal processing circuit such as a color conversion circuit for converting image signals taken by a CCD, or the like, and read out to provide the luminance signal and the color difference signal must be provided at the camera side, and the problem arises that the connection cable becomes thick.
In other words, because the image signals are converted to the luminance signal and the color difference signal in the video camera, signal lines for the luminance signal and for the color difference signal must be prepared when these signals are transferred to the image input device.